As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER TAKEOFF, THE CREW FELT YAW MOVEMENT AS ENGINE NR 2 TORQUE DROPPED TO 30 PERCENT FOR A MOMENT THEN CAME BACK TO NORMAL. THE CREW OPTED TO TURN AND LAND BACK AT THE POINT OF DEPARTURE. TROUBLESHOOTING IS FOCUSING ON A POSSIBLE FAULTY NH SPEED SENSOR.